1. Field of the Invention
The invention relates in general to a video card, and more particularly to a video card with a keyboard/video/mouse over IP (KVM over IP) function.
2. Description of the Related Art
The video card functions to control the graphic output of the computer. The video card has to be mounted to the computer mainboard and connected to the display such that the display can display the data. So, the video card may be regarded as a data transmission interface between the computer host and the display. The function of the video card often determines the display quality of the display.
In addition, the KVM over IP technology provides the function of controlling multiple local computers by a remote computer through the network. FIG. 1 is a block diagram showing the structure of a conventional KVM-over-IP-device connected to a video card to transfer data. The video card 100 includes a PCI (Peripheral Component Interface) or AGP (Accelerated Graphics Port) (PCI/AGP) controller 102, a PCI/AGP bus interface 104, a video memory 106 and a D/A converter (Digital-to-Analog Converter) 108. The control unit 101 transfers the video data Dv to the controller 102 through the bus interface 104. The controller 102 computes (processes) the video data Dv and then stores the processed data into the video memory 106. The D/A converter 108 converts the video data Dv into analog data Da, which is inputted to the KVM-over-IP-device 120 and then outputted to the display 109 for display.
Furthermore, the KVM-over-IP-device 120 includes an interface controller 122, a keyboard/mouse interface 123, a CPU (Central Processing Unit) 124, an A/D (Analog-to-Digital) converter 126 and a network interface 128. When the KVM-over-IP-device 120 is in a local mode, the keyboard/mouse data Dkm outputted by the keyboard/mouse console 121 is transferred to a keyboard/mouse port 125 of the local computer through the keyboard/mouse interface 123 in order to control the local computer. When the KVM-over-IP-device 120 is in the network mode, the remote computer 129 utilizes window client or Java client or browser software to control the local computer connected to the KVM-over-IP-device 120 through the operation of the keyboard/mouse and the network 127.
When the control unit 101 wants to transfer the video data Dv to the remote computer 129 through the network 127 using the KVM-over-IP-device 120, the video data Dv has to be converted into the analog data Da using the D/A converter 108, and then converted into the digital data Dd using the A/D converter 126. The digital data Dd is processed by the interface controller 122 and the CPU 124, and then outputted to the remote computer 129 through the network interface 128.
As mentioned above, the video card 100 has to use the D/A converter 108 and the A/D converter 126 in order to transfer the video data Dv to the remote computer 129 through the KVM-over-IP-device 120. Because the data error tends to be caused during the converting processes of the D/A converter 108 and the A/D converter 126, the precision of the data transmission is deteriorated, the transmission speed is reduced, and the manufacturing cost is thus increased.